Thanks to La Nina, it's cool to be a spider

Bridie Smith

THE outdoor furniture is so covered in cobwebs it resembles a prop from an Indiana Jones film. Meanwhile, each time you open the car door you plunge your fingers into a web that spans the length of the handle.

Welcome to summer in wet Melbourne. According to Mark Elgar, from the University of Melbourne's department of zoology, we're in for a bumper spider season.

''We've had a mild and wet winter and spring and I think it's going to be packed full of spiders and insects,'' Professor Elgar said.

The brown house spider Photo: Minibeast Wildlife

The humid conditions suit spiders as they produce an abundance of insects for the spiders to eat. A prolific food supply inevitably leads to prolific breeding.

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''We've gone through a bust and now these insects and spiders are enjoying a boom, which will last as long as the La Nina cycle lasts,'' he said.

An evolutionary biologist, Professor Elgar said some species such as golden orb weaving spiders were rarely seen in recent years but now were increasingly common in suburban backyards. Wandering spiders, named so because they walk on the ground, are also more active at this time of year when they mature.

Wolf spider Photo: Museum Victoria

He also added spiders were probably more noticeable because they had been conspicuous in their absence during the drought years, which ended with the arrival of La Nina.

While there is no such thing as a ''spider census'', Professor Elgar said the spider surge was hard to miss. In years past, when he travelled to northern Victoria to collect orb weaving spiders for research, he could spend three or four hours trying to find two or three specimens. Now he can collect 100 in half an hour.

Among the more common spiders found in Melbourne's homes and backyards are the black house spider, the huntsman, the daddy long-legs and the brown house spider. White-tailed spiders, which feed on black house spiders, are also tipped to grow in number as their prey population booms.

Huntsman spider Photo: Museum Victoria

However, Museum Victoria animal keeper Colin Silvey said only a fraction of Australia's 20,000 spider species were dangerous.

''Apart from the red back, most spiders found in the home are harmless,'' he said.

And rather than lament the spider surge, he said, there was a silver lining, as spiders are also known as nature's pest controllers. White-tailed spiders eat the black house spiders, which tend to live on window sills, while daddy long-legs feed on silverfish.

The black house spider Photo: Museum Victoria

Mr Silvey said the boom was occurring around Australia wherever plant and insect growth flourished due to rain.

''As the La Nina event has been predicted to continue through this summer, the spider populations should boom,'' he said. ''It should be quite large, not only because of increased resources but through last season's heightened breeding success.''

Meet your housemates: common spiders found in Melbourne's homes and backyards

Huntsman spider

Huntsman spiders are the large, hairy spiders often found inside homes. Although they are the spiders of nightmares and provoke the loudest screams, Huntsman spiders are actually timid and relatively harmless. They eat insects and other spiders.

Daddy long-legs spider

Daddy long-legs spiders are probably the most common spider found indoors. They make their webs behind doors, around furniture, in garages and sheds and in the corners of ceilings. They feed on small insects, silverfish and other spiders.

Brown house spider

The brown house spider has a similar body shape and web to the red-back spider, but lacks the red-back's distinctive red stripe. It is often found indoors and prefers dark places such as in cupboards or under furniture.

White-tailed spider

White-tailed spiders are frequent visitors to our homes, particularly our bedrooms. They are nocturnal hunters and feed mainly on other spiders, especially black house spiders.

Black house spider

Black house spiders make distinctive lacy webs with several funnel-shaped entrances. Webs are common in the corners of window frames and on paling fences. These timid spiders appear only when prey is caught in their web.

Wolf spider

Wolf spiders are ground-dwelling hunters. The female carries her egg sac underneath her abdomen until the spiderlings hatch. The spiderlings then ride on their mother's back for several weeks. This behaviour occurs also in scorpions.